Science at key stage 3 (Year 9)
Unit 9I: Energy and electricity
Section 6: d. How does electricity transfer energy?
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Objectives |
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- that a cell has chemical energy, which is transformed to electrical energy in a circuit
- to consider which factors are important and how to vary them
- to choose appropriate techniques and equipment
- to explain results that do not fit a pattern that arises
- to compare their investigative method and results with those of others and evaluate the work in the light of comparisons
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Activities |
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Outcomes |
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Children: |
- Show the inside of a dry cell. Establish that there is a chemical change when a battery/cell produces a current. Associate the energy of the chemical change with input to a circuit.
- Ask pupils to plan an investigation into how to make a cell from a fruit or vegetable to produce the highest voltage,
eg the performance of a particular fruit with a range of electrode sizes, separations or metal combinations, the relative effectiveness of different fruit. If appropriate, link to work on the relative reactivity of different metals.
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- describe energy transformation from a cell/battery to a circuit
- identify and describe patterns in data
- draw conclusions from their data
- describe how to improve their work,
eg by identifying strengths in the work of others
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Points to note |
- Reactivity of metals is covered in unit 9F 'Patterns of reactivity'.
Safety
- a dry cell contains hazardous chemicals. The use of solutions such as vinegar or lemon juice provides a cheaper alternative to a range of fruits. The size of the voltage depends mainly on the difference in reactivity of the metals used as electrodes,
eg the best will probably be copper and magnesium, giving about 1.5V
- pupils' plans should be checked for health and safety before practical work begins
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This unit is divided into sections. Each section contains a sequence of
activities with related objectives and outcomes. You can view this unit by
moving through the sections or print/download the whole unit.
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